Ethylene-vinyl acetate-allyl glycidyl ether terpolymer with polyvinyl chloride

ABSTRACT

Specific copolymers of ethylene, a vinyl ester, and allyl glycidyl ether are disclosed as being particularly suitable plasticizers for polymers such as polyvinyl chloride. The copolymers have a molecular weight of about 400-3,000 and comprise 15-40 weight percent ethylene, 35-70 weight percent vinyl ester, and 15-35 weight percent allyl glycidyl ether.

United States Patent 11 1 Adelman Mar. 27, 1973 [541 ETHYLENE-VINYLACETATE-ALLYL GLYCIDYL ETI-IER TERPOLYNIER WITH POLYVINYL CHLORIDE [75].Inventor: Robert Leonard Adelman, Wilmington, Del.

[73] Assignee: I. du Pont de Nemours and Company, Wilmington, Del.

[22] Filed: July 29, 1971 v {21] App]. No.: 167,467

Related US. Application Data [60] Division of Ser. No. 843,858, July 22,1 969, which is a continuation-in-part of Ser. No. 441,354, March 19,1965, abandoned.

52 US. Cl ..260/836, 26 0/45.7 P, 260/45.75 R, 260/4575K,260/80.72,260/830 P [51] Int. Cl. ..C08g 45/04 58 Field of Search..260/836 Priniary Examiner-Paul Lieberman AttorneyThomas E. CurrierABSTRACT Specific copolymers of ethylene, a vinyl ester, and allylglycidyl ether are disclosed as being particularly suitable plasticizersfor polymers such as polyvinyl chloride. The copolymers have a molecularweight of about 400-3,000 and comprise 15-40 weight percent ethylene,35-70 weight percent vinyl ester, and 15-35 weight percent allylglycidyl ether.

. 4 Claims, No Drawings ETHYLENE-VINYL ACETATE-ALLYL GLYCIDYL ETIIERTERPOLYMER WITH POLYVINYL CHLORIDE CROSS REFERENCE TO RELATEDAPPLICATIONS This application is a division of application Ser. No.843,858, filed July 22, 1969, which is a continuationin-part of pendingapplication Ser; No. 441,354, filed to azo dicycl'ohexane carbonitrile.While reaction tem- Mar. 19, 1965, now abandoned.

BACKGROUND OF INVENTlON While it has been disclosed in the patentliterature (U. S. Pat. No. 2,703,794) that ethylene/vinyl ester systemscan have minor amounts of a third component such as allyl glycidylether, there is no disclosure that, within aspecified range, copolymersof ethylene/vinyl ester/allyl glycidyl ether would possess propertiesmaking them eminently suitable in themselves as plasticizers forpolymers such as polyvinyl chloride.

The bulk of the plasticizer requirement has heretofore been satisfiedwith esters of phthalic acid, in particular, dioctyl phthalatel-lowever, the vapor pressure of the phthalate esters is not as low aswould be desirable for best performance as plasticizers. Also, thesemonomeric plasticizers tend to migrate to the polymer surface, and areeasily extracted by organic solvents or tend to be washed away byaqueous solutions of detergents. The industry has also preparedpolymeric plasticizers, which have better long-term aging (lowervolatility) and sometimes lower extractability with organic solventssuch as alcohol or aliphatic hydrocarbons. However, only the highestquality and most expensive polymeric plasticizers, such as polypropylenesebacate, have good resistance to aqueous alkali as well as good organicsolvent resistance. Also, these polymeric plasticizers tend to beextracted from vinylcoated fabrics when they are submitted todry-cleaning solvents. Further, even if extraction is slow, the vinylcomposition is greatly weakened by exposure to such solvents, due to theswelling effect of the latter. Thus,

there is a real need for better and cheaper plasticizers for polyvinylchloride resins. Mixtures of complex aromatic hydrocarbons have alsobeen utilized for this purpose but' are dark in color and have poorcompatibility with the polyvinyl chloride resins.

SUMMARY OF INVENTION According to the present invention, there-areprovided addition-type copolymers of ethylene/vinyl ester/allyl glycidylether having a molecular weight in the range of about 4003,000 whichconsist essentially of -40 percent ethylene by weight, 3570 percentvinyl ester by weight and 1535 percent allyl glycidyl ether by weight.Preferably, the vinyl ester contains from 1-6 carbon atoms in the acidmoiety. As used herein, the term consisting essentially of means thatthe recited components are indispensibly necessary; however, othercomponents which do not prevent the advantages of the invention frombeing realized can also'be present.

DESCRIPTION OF PREFERRED EMBODIMENTS The copolymers of this inventioncan be prepared, in general, by contacting, reacting and heatingtogether,

in the presence of a free radical initiator, and an oxygen-freeatmosphere, at a temperature of about 60160C. and an ethylene pressureof about 70-1 ,000 atmospheres amixture of a monomeric vinyl ester andmonomeric allyl glycidyl ether. Among the free radical'initiators whichcan be used are such peroxides as benzoyl peroxide, lauroyl peroxide,ditertiary butyl peroxide and tert butyl perbenzoate, azo initiatorssuch as alpha,alpha-azobisisobutyroni-trile and peratures of 60160C. andpressured of -1 ,000 atmospheres of ethylene can be used, it ispreferred to utilize a temperature range of about 70-90C. and ,anethylene pressure of about 400-600 atmospheres for bulk polymerizationscarried out in batch processes. Chain transfer agents such as aldehydesor mercaptans can also be used. However, with a concentration of allylglycidyl ether of at least 20 percent of the total monomer content, noadditional ch'ain transfer agents are necessary to obtain molecularweights of the copolymer of this invention in the range of about900-1500.

Weight ratios of the polyvinyl chloride or similar polymer to thecopolymer of this invention can be as low as 10/90 or as high as 98/2,depending upon the utility to which the composition is to be put. Thushighly flexible, soft, tough products are possible with the lowconcentrations of polyvinyl chloride, while quite stiff, hard, yetshock-resistant products are possible with high concentrations of thepolyvinyl chloride.

When used as plasticizers for polyvinyl chloride or 1 similar polymers,low molecular weight copolymers,

e.g.,' 400-l,500 and especially 400-900, are particularly suitable whenthe plasticized compositions are to.

blend easily put into its desired form. In such post curing instances,the high volatility of the copolymer is not a problem since it ispolymerized to a much, higher molecular weight in the curing step. Wherecuring is not to be accomplished, molecular weights of SOD-3,000 areacceptable with 500-],500 being preferred.

Blends of the copolymer and the polyvinyl chloride resin can be preparedby any conventional method. For example, a suitable blend may beprepared by milling on a hot roll mill, by casting from a solvent, suchas tetrahydrofuran or cyclohexanone, or by working the plasticizer intoa dry polyvinyl chloride resin powder to form dry powder blends orsuspensions. Solvent systems are particularly suitable with blendscontaining copolymers with molecular weights of 1-,500-3,000. can beobtained by heatingto l50-l C. for 5-30 minutes. The resulting blendsare clear, homogeneous and very light in color. Of course, if opaqueand/or colored compositions are desired, conventional pigments, dyes,extenders or fillers can be used to accomplish the desired result.

In addition, if further stability to heat and light is desired, smallamounts of stabilizers well known to the plasticized vinyl resin art canalso be added, such as cadmium compounds, cadmium-barium salt blends,lead phosphites, tribasic lead sulfate or other lead salts,

organic phosphites, organo-tin or tin salts, organic phosphates.

For a clearer understanding of the invention, the following specificexamples are given. These examples are meant to be merely illustrativeof the invention and not in limitation thereof. Unless otherwiseindicated, parts and percentages are expressed on a weightbasis.

EXAMPLE 1 To a stainless steel rocker bomb having a capacity of 400milliliters, there was added a mixture of 40 grams of allyl glycidylether, 120 grams of vinyl acetate and grams of benzoyl peroxide. Therocker bomb was then evacuated, flushed with nitrogen, reevacuated andpressured to 470-500 atmospheres with ethylene. The rocker was thenstarted and the temperature brought to and maintained at 80C. for aperiod of 6 hours. The unchanged allyl glycidyl ether and vinyl esterwere removed by evaporation under reduced pressure at 5060C. There wasrecovered a conversion product of 78 grams of viscous liquid..Based uponan epoxide analysis (HCl in pyridine) and from an elementalcarbon-hydrogen analysis, the percentage composition of theethylene/vinyl acetate/allyl glycidyl ether copolymer was 36/49/15.Ebullioscopic molecular weights were calculated withthe firstdetermination being 1,330 and the second 1,350. The, epoxy equivalentwas calculated as 760 with the average.

number of epoxy groups/chain being l .8 and with bulk viscosity inpoises at 60C. being less than 148.

EXAMPLE 2 To a stainless steel rocker bomb having a capacity of 400milliliters, there was added a mixture of 80 grams of allyl glycidylether, 80 grams of vinyl acetate and 5 grams of benzoyl peroxide. Therocker bomb was then evacuated, flushed with nitrogen, reevacuated andpressured .to 460-500 atmospheres with ethylene. The rocker was thenstarted and the temperature brought to and'maintained at 80C. for aperiod of 6 hours. The unchanged allyl glycidyl ether and vinyl esterwere removed by evaporation under reduced pressure at 50-60C. There wasrecovered a conversion product EXAMPLE 3 To stainless steel rocker bombhaving a capacity of 400 milliliters, there was added a mixture of 80grams of allyl glycidyl ether, 80 grams of vinyl acetate and 5 grams ofbenzoyl peroxide. The rocker bomb was then evacuated, flushed with.nitrogen, reevacuated and pressured to900 to 980 atmospheres withethylene. The rocker was then started and the temperature brought to andmaintained at 80C. for a period of 6 hours. The unchanged allyl glycidylether and vinyl ester were removed by evaporation under reduced pressureat 5060C'. There was recovered a conversion product of 47 grams of aviscous liquid. Based upon an epoxide analysis (HCl in pyridine) andfrom an elemental carbon-hydrogen analysis, the percentage compositionof the ethylene/vinyl acetate/allyl glycidyl ether copolymer was40/36/24. Ebullioscopic molecular weights were calculated with the firstdetermination being 1,020 and the second 1,150. The epoxy equivalent wascalculated as 475 with the average number of epoxy groups/chain being2.2 and with bulk viscosity in poises at 50C. being 43.

EXAMPLE 4 of 36 grams of a viscous liquid. Based upon an epoxideanalysis (HCl in pyridine) and from an elemental carbon-hydrogenanalysis, the percentage composition of the ethylene/vinyl 1propionate/allyl glycidyl ether copolymer was 18/52/30. Ebullioscopicmolecular weights were calculated with the first determination being 980and .the second 1,000. The average number of epoxy groups/chain was 2.6and the bulk viscosity in poises at 27C. being 98.5.

EXAMPLE 5 To a stainless steel rocker bomb having a capacity of v 500milliliters, there was-added a mixture of 40 grams of allyl glycidylether, 120 grams of vinyl propionate and 5 grams of benzoyl peroxide.The rocker bomb was then evacuated, flushed with nitrogen, reevacuatedand pressured to 68 atmospheres with ethylene. The rocker was thenstarted and the temperature brought to and maintained at 80C. for aperiod of 6 hours. The unchanged allyl glycidyl ether and vinyl esterwere removed by evaporation under reduced pressure at S0-60C. There wasrecovered a conversion product of 70 grams of a viscous liquid. Basedupon an epoxide analysis (HCl in pyridine) and from an elementalcarhon-hydrogen. analysis, the percentage composition of theethylene/vinyl propionate/allyl glycidyl ether copolymer was 18/66/16.Ebullioscopic molecular weights were calculated with the firstdetermination being 1,300 and the second 1,310,. The average number ofepoxy groups/chain was 1.9 and the bulk viscosity in poises at 27C. wasapproximately 148, and at 50C. was in the range of from about 46-63.

EXAMPLE 6 To a stainless steel rocker bomb having a capacity of 500milliliters, there was added a mixture of grams of allyl glycidyl ether,80 grams of vinylpropionate and 5 grams of benzoyl peroxide. The rockerbomb was then evacuated, flushed with nitrogen, reevacuated andpressured to 500 atmospheres with ethylene. The

rocker was then started and the temperature brought to and maintained at82C. for a period of 6 hours. The

bon-hydrogen analysis, the percentage composition of the ethylene/vinylpropionate/allyl glycidyl ether copolymer was 36/42/22. Ebullioscopicmolecular weights were calculated with the first determination being1,200 and the second 1,140. The average number of epoxy groups/chain was2.2 and the bulk viscosity in poises at 27C. was 46-63.

EXAMPLE 7 Table 1 provides a comparison of the mechanical properties andextraction characteristics of various plasticizers. ln testing, sampleswere conditioned in a constant temperature room at 72F. and 50 percentrelative humidity for a least 16 hours before tests were carried out.Relative volatilities were determined by p the weight loss of 0007-0014inch thick films which .were hung in a circulating air over at 85C. for48 mineral oil (Primol D, Esso Standard Oil Co.) at 72F for 10 days, theoil being changed after the fifth day. The films were dried withcheesecloth, conditioned, wiped dry again with cheesecloth andreweighed.

Blends were prepared either by (1) working 10-12 gm. samples of polymer,plasticizer, and stabilizer (if used) on a conventional small rubbermill for l0 TAB LE 1 minutes or 2) mixing plastisol grade 100 percentpolyvinyl chloridewith the plasticizer for 15 minutes. Bars wereprepared by compression molding the sheet or plastisol in a stainlesssteel race, cut out to give 2.2

7 inch X 0.6 inch X 0.065 inch moldings, and between aluminum sheets at170C. for 5min. at 2,000 p.s.i.

Very thin films (0.008 inch) for volatility tests were obtained bycompression molding at the above conditions, but without the use of anyshims. Films 0.020

1 inch thick for extraction tests were prepared by compression moldingat 150C. for 5 minutes at 2,000 p.s.i. between 10 mil shims.

The mechanical properties which are shown in Tables l and 11 weredetermined as follows. The tensile strength was determined on fourdumbbell-shaped specimens which were stamped out of 2.2 inch X 0.6 inchX 0.065 inch moldings. The dumbbell dimensions were such that the lengthwas 2 inches, the bell-shaped areas were 0.3 inch in width, and theelongated center sections were 1 inch X 0.10 inch X 0.065 inch. Thesamples were pulled in the lnstron, C-cell, at 10 inches per minutecrosshead speed and the distance between jaws being 1 inch (strain rate1,000 percent per minute). The elongation at break was estimated by thejaw separation at break (the differences between the jaw separation atbreak and the 1 inch bench marks placed on the neck of the specimenbefore pull were negligible). Loads at 40 percent elongation andl40percent'elongation were read off the stress-elonga- 7 tion chart ofthe tensile strength chart.

Table 11 illustrates the resistance to extraction by dry-cleaningsolvents and to gasoline/and also the mechanical properties'which areobtained from polyvinyl chloride plastisols based on the ethylene/vinylacetate/ally] glycidyl ether copolymers formulated with various reactivecomponents. Extraction by gasoline was determined by the weight loss of0.008 inch to 0.020 inch thick' film which were immerced in white,non-leaded gasoline for 1 hour at 72C. The specimens were wiped withcheesecloth, dried' at C. for 45 min. in a circulating air oven andreconditioned as hereinbefore. Sensitivity to perchloroethylenewasestimated by the weight loss of 0.065 inch discs which were immersedin the solvent for 24 hours at 72F.

Extraction *Polyvinyl Chloride/ Plasticizer Mechanical Plasticizer RatioComposition Color Properties Volatility Oil Gas Tide 2}] Dioctylphthalate fair-'poor excellent fair 6.6 25.0 1.8 2/1 Harflex300(polyester fair good good 3.6 1.7 10.1

mfgd. by Wallace and Tiernan Company) 2/1 Paraplex (3-25 (polyprofairgood good 7 0.4 0.6 1.7

- pylene sebacate mfgd. by

Rohm & Haas Co.) 2/1 E/Vac/AGE excellent good good 0.2 0.1 1.1

(36/49/15) 2/1 E/Vac/AGE excellent good good 0.2 1.0 2.1

35/40/25) 2/1 E/V Prop/AGE excellent fair-good good 0.07 0.81 2.1

(18/52/30) mol. wt. 990 2/1 E/V Prop/AGE excellent fair good 0.07 0.601.0

*Geon 101", a high molecular weight polyvinyl chloride manufactured byGoodrich Rubber Company.

TABLE 11 Percentage Weight Loss Composition with Percent Perchloro- 40percent Geon 121" polyvinyl in total ethylene Tensile Elongation Moduluschloride composition (Perclene) Gasoline (p.s.i.) (p.s.i.)

1) Dioctyl phthalate 30 30 30 1960 230 470 2) "Harflex 300 30 30 1.62660 325 630 3) Paraplex 6-25 30 1.5 2670 260 840 v 50 1960 380 330 4)E/Vac/AGE (40/36/24 and 33 4.4 1.9 3930 43 3,830

mol. wt. of 1090) Tetrapropenylsuccinic l7 anhydrideTri(dimethylaminomethyl) 2 p enol 5) E/Vac/AGE (40/36/24 and 37 4.8 2.72270 140 L360 mol. wt. of 1090) Diethyl chlorophosphate l2Tri(dimethylaminomethyl) 0.5 phenol 6) E/Vac/AGE (40/36/24 and 0.3 1.9

Althoughthe examples hereinbefore have illustrated.

the use of the novel copolymer of this invention as a plasticizer forpolyvinylchloride, it should be obvious that the beneficial results canalso be achieved when used with such polymers as polyvinyl esters,polyvinyl formals, polyvinyl butyrals, ethylene/vinyl acetate copolymersand terpolymers and polyamides. Additionally, the term polyvinylchloride resin is meant to include copolymers of vinyl chloride withvinyl esters such as vinyl acetate, acrylate esters, such as methylacrylate or ethyl acrylate, fumarate, maleate esters such as dimethylmaleate, the half-esters of fumarate, maleic or itaconic acid, withvinylidene chloride, vinyl fluoride, ethylene and other polymerizablemonomers containing a single double bond. Also, terpolymers of vinylchloride, vinyl acetate and maleic acid or other saturated acids orpartial hydrolyzed copolymers of vinyl chloride and vinyl esters can beplasticized with the novel copolymers of this invention. In all.thesecopolymers, the vinyl chloride predominates and should provide at least83 percent by weight of the polymer.

Among the polymers hereinbefore mentioned, those which receiveparticular advantages are polymers containing a minor percentage of apost-reactive group such as -OH, COOH, -NH and --SH, which on heatingwith the novel copolymers of this invention will lead to a 100 percenthomogeneous, coalesced, crosslinked composition, yet before heatingexist as a physical mixture, i.e., a semi-liquid or viscous liquidsuspension or dry powder blend, which can easily be added to molds orcoating or extrusion equipment.

The present invention provides novel copolymers which are efficientpolymeric plasticizers for polyvinyl chloride resins and additionallyconfer a superior level of oil, gasoline and detergent resistance (seeTable 1). Moreover, the novel copolymers of this invention have theadditional quality of being excellent heat stabilizers and reduce'oreliminate the need for providing a 2-5 percent by weight epoxystabilizer and 2-4 percent by weight barium or cadmium salts or otherstabilizers as hereinbefore mentioned which are found in the usualplasticizer formulation. Inasmuch as the latter additives are generallysusceptible to extraction by such organic solvents as gasoline, thenovel copolymers of this invention have superior durability and agingproperties as compared to polyvinyl chloride resin formulationscontaining conventional stabilizers and plasticizers. A formulation ofthe novel copolymers of this invention with a minor amount of diethylchlorophosphate or tetrapropenyl succinic anhydride exhibit greatlyreduced extractability with respect to dry-cleaning solventssuch asperchloroethylene (see Table II). Additionally, the hereinbeforeformulations demonstrate a lower rate of change of .stiffness withtemperature changes than do commercial polymeric plasticizers.

Polyvinyl chloride resins, plasticized with the copolymers of thisinvention, have been extended with diallyl phthalate and maleicanhydride to give workable dry powder mixes of plastisols. Afterapplication and upon being cured with peroxides and heating, the

resulting products are flexible, tough, solvent resistant andexhibitgood adhesion with respect to aluminum 5 surfaces.

Since many different embodiments of this invention may be made withoutdeparting from the spirit and scope thereof, it is to be understood thatthe invention 7 is not limited by the specific illustrations except tothe extent defined in the following claims.

What is claimed is:

l. A composition comprising (a) from about 2-90 percent by weight of anaddition type copolymer of ethylene, a vinyl ester, and allyl glycidalether, said copolymer having a molecular weight in the range of about4003,000 andconsisting essentially of about 15-40 percent by weightethylene, about 35-70 percent by weight vinyl ester having one to sixcarbon atoms in the acid moiety, and about 15-35 percent by weight-allylglycidyl ether, and (b) fromabout 98-10 percent by weight of a vinylchloridepolymer contain-' ing at least 83 percent by weight of combinedvinyl chloride.

2. The composition of claim 1 wherein said vinyl ester is vinyl acetate.

3. The composition of claim 1 wherein said vinyl ester is vinylpropionate.

4. The composition of claim 1 wherein said copolymer has a molecularweight of 500-1 ,500.

2. The composition of claim 1 wherein said vinyl ester is vinyl acetate.3. The composition of claim 1 wherein said vinyl ester is vinylpropionate.
 4. The composition of claim 1 wherein said copolymer has amolecular weight of 500-1,500.